Cyclooxygenases (COX) are enzymes catalyzing arachidonic acid into prostanoids. COX exists in three isoforms: COX-1, 2, and 3. COX-1 and COX-2 have been widely studied in order to explore and understand their involvement in Alzheimer's disease (AD), a progressive neuroinflammatory dementia. COX-2 was traditionally viewed to be expressed only under pathological conditions and to have detrimental effects in AD pathophysiology and neurodegeneration. However, an increasing number of reports point to much more complex roles of COX-2 in AD. Mammalian/mechanistic target of rapamycin (mTOR) has been considered as a hub which integrates multiple signaling cascades, some of which are also involved in AD progression. COX-2 and mTOR are both involved in environmental sensing, growth, and metabolic processes of the cell. They are also known to act in cooperation in many different cancers and thus, their role together in normal cellular functions as well as AD has been explored in this review. Some of the therapeutic approaches targeting COX-2 and mTOR in AD and cancer are also discussed.

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Nanoparticles are used in various biomedical applications like in vitro diagnostics, imaging, drug delivery, and other therapeutic uses. The performance of such applications requires accurate knowledge of size distribution that needs precise characterization techniques. In this study, a single‐nanoparticle characterization system based on the total internal reflected scattering signal (SNC‐TIRS) is demonstrated for the size estimation of synthetic nanoparticles and exosomes. A compact waveguide‐based evanescent field illumination is used to convert a digital microscope into a nanoparticle characterization system based on scattering signals from diffusing nanoparticles in Brownian motion. By analyzing single‐particle trajectories, the system estimates the hydrodynamic size, average number of particles observed per unit volume, and the distribution of sample heterogeneity. SNC‐TIRS is benchmarked with inorganic nanoparticles and biomaterials in size range of 80–250 nm. Its utility to characterize the size of exosomes isolated from plasma using magnetic nanoparticles (MNPs) is shown. The hydrodynamic size of bare MNPs (123.83 ± 29.19 nm), antibody‐bound‐MNPs (161.33 ± 29.47 nm), and antibody‐exosome‐bound‐MNP conjugates (224.82 ± 25.89) are estimated and the results obtained agree with standard methods such as dynamic light scattering and nanoparticle tracking analysis. SNC‐TIRS can enable the label‐free characterization of nanomaterials and clinically relevant biomarkers.